The present invention relates to a horizontal-synchronizing-pulse measuring circuit for measuring the number of horizontal synchronizing pulses.
There has conventionally been known that, for example, in an IC (integrated circuit) such as for a CRT (cathoderay tube) character generator which displays a character or the like at a desired position on a CRT, the vertical position of such character on the CRT is set by the measurment of the number of horizontal synchronizing pulses after the occurrence of a vertical synchronizing pulse. The detailed explanation of the structure and operation of such a conventional horizontal-synchronizing-pulse measuring circuit will be given later before the preferred embodiments of the present invention are explained.
For a horizontal-synchronizing-pulse measuring circuit to be used, for example, in a character generator for a VTR, it is desired for the circuit to prevent any vertical vibration from occurring on a screen of a CRT. The present invention provides a measuring circuit which meets such a desire.